Microsoft Patch Tuesday, May 2017

Microsoft is releasing 56 CVEs for the May 2017 Patch Tuesday today. This includes 15 CVEs rated "Critical", 40 rated "Important" and one rated "Moderate". Across them all these vulnerabilities there are security updates for the following software and services:

Internet Explorer

Microsoft Edge Browser

Microsoft Windows

Microsoft Office and Microsoft Office Services and Web Apps

Microsoft Scripting Engine

Windows SMB

.NET Framework

Adobe Flash Player

Windows DNS Server

Microsoft SharePoint

As always you'll want to make sure that your Windows clients are set to auto-update which will take care of the patches for Internet Explorer, Office, Edge and Windows itself. Of particular concern is the wide array of patches issued to Windows SMB, the common protocol used in all Windows networks to share data and information. A full quarter of this month's release (13 CVEs) affect this protocol suite from Information Disclosure, Denial of Service and critical Remote Code Execution vulnerabilities. Remote Code Execution vulnerabilities also affect the Microsoft Scripting Engine that could be exploited just by visiting a malicious website.

On the server side of things, the Microsoft DNS server is getting a patch for a Denial of Service vulnerability. There's also a Cross Site Scripting vulnerability in Sharepoint and a Privilege Escalation vulnerability in the Hyper-V platform.

In a rare move Microsoft actually released an out of band patch the day before Patch Tuesday. On Saturday May 5th Google Project Zero researcher Tavis Ormandy announced on Twitter that he and colleague Natalie Silvanovich "discovered the worst Windows remote code exec in recent memory." He later added that the "Attack works against a default install, don't need to be on the same LAN and it's wormable"

Well we didn't need to wait until Patch Tuesday to get a patch for this one. The issue in question is a critical Remote Code Execution vulnerability in Microsoft Malware Protection Engine (aka Defender) (https://technet.microsoft.com/en-us/library/security/4022344). The quick and agile patch was applauded even by Ormandy, who tweeted shortly after the patch was released "What an amazing response, thanks so much Simon and MSRC! That was incredible work." The patch should be automatically applied without any user interaction.